Hello Greyshark.
Thank you for taking the time to share such detailed feedback. We are glad to hear you have had a great experience with your mower and blower, especially in terms of power, runtime, and versatility. We are sorry to hear that your experience with the 80V 16" string trimmer (ST80L00) has not met the same expectations, particularly around line feeding and ease of use.
Based on what you have described, frequent jamming and line breakage are often related to how the trimmer line is installed or the type of line being used. We recommend ensuring the line is wound evenly and tightly in the correct direction indicated on the spool, overlapping or loose winding can prevent proper feed. Using the correct diameter line specified for the unit is also important, as thicker or lower-quality line can increase resistance and lead to jamming. Additionally, avoid overfilling the spool, as this can restrict movement and cause the line to bind. If the line is brittle or breaking frequently, soaking it in water for 12- 24 hours before use can improve flexibility and reduce snapping during operation. It may also help to tap the bump head firmly on a hard surface while running at full speed to advance the line properly, and periodically check the spool housing for debris that could interfere with smooth feeding. Here is a video showing how to replace the trimmer line (https://youtu.be/pq8-50ztebo). If the unit still feels heavier than expected, adjusting your grip or adding a shoulder strap like our exoFLEX Shoulder Strap for String Trimmer / Leaf Blower (SKU 80023302) can improve handling and reduce fatigue during use. We appreciate your honest feedback regarding the trimmer experience, and we will be sure to share this with our product team. If you would like additional support our team is always here to assist and ensure you get the best possible performance from your tool. They can be reached either using the online chat function, on Greenworks Tools page, or by calling 1-888-909-6757.